Update primary index functionality

Author: simon-dew

modules/n1ql/pages/n1ql-language-reference/createprimaryindex.adoc

@@ -19,7 +19,7 @@ include::partial$n1ql-language-reference/horizontal-style.adoc[]
 
 The `CREATE PRIMARY INDEX` statement allows you to create a primary index.
 Primary indexes contain a full set of keys in a given keyspace.
-Primary indexes are optional and are only required for running ad hoc queries on a keyspace that is not supported by a secondary index.
+Primary indexes are optional -- they enable you to run ad hoc queries on a keyspace that is not supported by a secondary index.
 
 == Purpose
 
@@ -62,7 +62,7 @@ image::n1ql-language-reference/create-primary-index.png["Syntax diagram: refer t
 [horizontal]
 index-name::
 (Optional) A unique name that identifies the index.
-If a name is not specified, the default name of `#primary` is applied. [small]##[<<note-index-name>>]##
+If a name is not specified, the default name of `#primary` is applied.
 +
 Valid GSI index names can contain any of the following characters: `A-Z` `a-z` `0-9` `&num;` `&lowbar;`, and must start with a letter, [`A-Z` `a-z`].
 The minimum length of an index name is 1 character and there is no maximum length set for an index name.
@@ -77,9 +77,6 @@ Refer to <<index-using>> below.
 index-with:: (Optional) Specifies options for the index.
 Refer to <<index-with>> below.
 
-[[note-index-name,note]]
-NOTE: You can drop unnamed primary indexes using the `DROP PRIMARY INDEX` statement, and named primary indexes using the `DROP INDEX` statement.
-
 [[if-not-exists]]
 === IF NOT EXISTS Clause
 

modules/n1ql/pages/n1ql-language-reference/dropindex.adoc

@@ -13,8 +13,11 @@
 include::partial$n1ql-language-reference/horizontal-style.adoc[]
 
 {description}
-Dropping an index that has replicas will also drop all of the replica indexes too.
-You can drop unnamed primary indexes using the {drop-primary-index}[DROP PRIMARY INDEX] statement.
+Dropping an index that has replicas will drop all of the replica indexes too.
+
+[NOTE]
+To drop a primary index, use the {drop-primary-index}[DROP PRIMARY INDEX] statement.
+For compatibility with legacy versions of Couchbase Server, you can also use the DROP INDEX statement to drop a named primary index.
 
 == Prerequisites
 

modules/n1ql/pages/n1ql-language-reference/dropprimaryindex.adoc

@@ -1,5 +1,5 @@
 = DROP PRIMARY INDEX
-:description: The DROP PRIMARY INDEX statement allows you to drop an unnamed primary index.
+:description: The DROP PRIMARY INDEX statement allows you to drop a primary index.
 :page-topic-type: reference
 :imagesdir: ../../assets/images
 
@@ -13,7 +13,7 @@ include::partial$n1ql-language-reference/horizontal-style.adoc[]
 
 {description}
 
-IMPORTANT: Named primary indexes that are created using CREATE PRIMARY INDEX can only be dropped using the DROP INDEX command.
+NOTE: For compatibility with legacy versions of Couchbase Server, you can also use the DROP INDEX statement to drop a named primary index.
 
 == Prerequisites
 
@@ -35,6 +35,9 @@ image::n1ql-language-reference/drop-primary-index.png["Syntax diagram: refer to
 // TODO: Automatic links in EBNF.
 
 [horizontal]
+index-name:: (Optional) A unique name that identifies the index.
+If you don't specify a name, the index with the default name of `#primary` is deleted.
+
 keyspace-ref:: (Required) Specifies the keyspace where the index is located.
 Refer to <<keyspace-ref>> below.